Most product ideas don't work
There are many reasons for an idea to not work out. Most commonly, customers just aren’t as excited about the idea as we are, so they choose not to use it (value risk). Sometimes it’s too complicated, or it’s more trouble than it’s worth (usability risk). Sometimes the users would love it, but it’s much more involved or expensive to build than we thought or hoped (feasibility risk).
The trick, then, is to figure out which ideas won’t work as fast as possible and then focus our efforts into the ones that are working.